1. Field of the Invention
This invention relates to a method for dimension conversion difference prediction, a method for manufacturing a photomask, a method for manufacturing an electronic component, and a program for dimension conversion difference prediction.
2. Background Art
Patterns in recent semiconductor devices have become remarkably finer. With the shrinkage of the design rule, it is more difficult to transfer a design pattern onto a wafer just as its desired features and dimensions. If any discrepancy occurs between the design pattern and the transferred pattern on the wafer, the deformation of the transferred pattern on the wafer may cause such problems as degradation in electrical characteristics and yield decrease due to bridges and breaks in the pattern.
To solve these problems, such processing as process proximity correction (PPC) is performed, which corrects the features of the mask pattern so that it is transferred just as the desired dimensions thereof.
In the steps of photolithography and etching, the dimensional accuracy of the feature to be formed is greatly affected by its layout environment of the other features placed therearound. Hence, a technique of process proximity correction processing is proposed, which uses the values of the dimension conversion difference determined stepwise in accordance with the distance between the opposed edges of opening features (see, JP-A 2004-363390(Kokai)). In the technique disclosed in JP-A 2004-363390(Kokai), on the basis of the line width and space width at a conversion difference prediction point, a value of the dimension conversion difference is selected from a set of stepwise predetermined values to predict the dimension conversion difference.
However, in the technique disclosed in JP-A 2004-363390(Kokai), the accuracy of dimension conversion difference prediction can be increased for linear features, but there is room for improvement in increasing the accuracy of dimension conversion difference prediction for nonlinear features (e.g., discontinuous and/or circular features) because of the effect of pattern features.